I getting ready to change the fluids in my transfer case, diffs and 5speed tranny. I looked in my owners manual and got the fluid weights out of that. The only problem is there wasn't any synthetic 80-90W. I got 75w-90 for everything. I got mobile 1 for the diffs and transfer and then I had to get royal purple for the tranny cause that's all that was left. Is 75-90 for everything alright.

 

For the diffs and transfer case... yes, 75-90 is fine. For the transmission, I can't help. I own automatics.

 

75-90 for the 5speed is good, just put the same stuff in both the tranny and tcase.

 

75w-90 Amsoil for me all around.

 

Go with a GL-4 lube for the transmission, like Redline's MT-90.

 

yeah, stick with a GL-4 in the trans. i believe the mobil1 is Gl-5. theres been alot of talk about the both so read your owners manual. per my 4runner manual, its says both are OKAY. Jason

 

I read in my owners manual that 4 and 5 were ok. I just went down to autozone to get the mobile1. I am thinking about taking the royal purple back though cause it was 16 a quart and the mobile was 8 or 9. I will just go somewhere else to get some mobile1. I haven't found anywhere in town that had redline or amisol and I don't have time to order it.

 

Napa had it.

Here's 4Crawler's writeup for what it's worth:
http://www.4crawler.com/4x4/index.sh...ntheticGearOil